RESUMEN
Lakes throughout the globe have been gravely altered or degraded at a pace much more significant than their restoration. In the heart of Srinagar, the summer capital of Jammu and Kashmir, Dal Lake, has witnessed extreme loss in water quality during the last four decades because of anthropogenic pressures. The lake is unique in that over 50,000 people inhabit the lake itself in houseboats, dongas, or islands within the lake. These people derive their livelihood from the lake in terms of tourism, agriculture, fishing, and vegetable farming. The countless ways people use the lake have led to an extreme load of pollution in the lake. Encroachment in and around the lake has led to the loss of volume of water in the lake and consequently increased the concentration of pollutants. Discharge of untreated sewage, agricultural runoff, and sediments from adjoining catchments have further degraded the lake water quality. The changes in water quality are clear from the physio-chemical properties of the lake waters. While transparency and dissolved oxygen in the lake have decreased drastically during the last 40 years, the concentration of harmful substances like phosphates, nitrates, and chlorides has increased. The hardness of water has also increased due to higher levels of carbonates and bicarbonates in the lake. This paper details the changes in the water quality of Dal Lake over the recent past. The paper analyses the strategies that can be implemented to manage the lake and restore its quality if appropriately implemented.
Asunto(s)
Lagos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Humanos , Lagos/química , Nitratos/análisis , Contaminantes Químicos del Agua/análisis , Calidad del AguaRESUMEN
The outbreak of COVID-19 pandemic has emerged as a major challenge from human health perspective. The alarming exponential increase in the transmission and fatality rates related to this disease has brought the world to a halt so as to cope up with its stern consequences. This has led to the imposition of lockdown across the globe to prevent the further spread of this disease. This lock down brought about drastic impacts at social and economic fronts. However, it also posed some positive impacts on environment as well particularly in the context of air quality due to reduction in concentrations of particulate matter (PM), NO2 and CO across the major cities of the globe as indicated by several research organizations. In China, Italy, France and Spain, there were about 20-30% reduction in NO2 emission while in USA 30% reduction in NO2 emission were observed. Compared to previous year, there was 11.4% improvement in the air quality in China. Drastic reductions in NO (-77.3%), NO2 (-54.3%) and CO (-64.8%) (negative sign indicating a decline) concentrations were observed in Brazil during partial lockdown compared to the five year monthly mean. In India there were about -51.84, -53.11, -17.97, -52.68, -30.35, 0.78 and -12.33% reduction in the concentration of PM10, PM2.5, SO2, NO2, CO, O3 and NH3 respectively. This article highlights the impact of lockdown on the environment and also discusses the pre and post lockdown air pollution scenario across major cities of the world. Several aspect of environment such as air, water, noise pollution and waste management during, pre and post lockdown scenario were studied and evaluated comprehensively. This research would therefore serve as a guide to environmentalist, administrators and frontline warriors for fighting our the way to beat this deadly disease and minimize its long term implications on health and environment.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , COVID-19 , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Brasil , China , Ciudades , Cambio Climático , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Francia , Humanos , India , Italia , Pandemias , Material Particulado/análisis , SARS-CoV-2 , EspañaRESUMEN
Candida albicans is an opportunistic fungal pathogen that can infect oral mucosal surfaces while being under continuous flow from saliva. Under specific conditions, C. albicans will form microcolonies that more closely resemble the biofilms formed in vivo than standard in vitro biofilm models. However, very little is known about these microcolonies, particularly genomic differences between these specialized biofilm structures and the traditional in vitro biofilms. In this study, we used a novel flow system, in which C. albicans spontaneously forms microcolonies, to further characterize the architecture of fungal microcolonies and their genomics compared to non-microcolony conditions. Fungal microcolonies arose from radially branching filamentous hyphae that increasingly intertwined with one another to form extremely dense biofilms, and closely resembled the architecture of in vivo oropharyngeal candidiasis. We identified 20 core microcolony genes that were differentially regulated in flow-induced microcolonies using RNA-seq. These genes included HWP1, ECE1, IHD1, PLB1, HYR1, PGA10, and SAP5. A predictive algorithm was utilized to identify ten transcriptional regulators potentially involved in microcolony formation. Of these transcription factors, we found that Rob1, Ndt80, Sfl1 and Sfl2, played a key role in microcolony formation under both flow and static conditions and to epithelial surfaces. Expression of core microcolony genes were highly up-regulated in Δsfl1 cells and down-regulated in both Δsfl2 and Δrob1 strains. Microcolonies formed on oral epithelium using C. albicans Δsfl1, Δsfl2 and Δrob1 deletion strains all had altered adhesion, invasion and cytotoxicity. Furthermore, epithelial cells infected with deletion mutants had reduced (SFL2, NDT80, and ROB1) or enhanced (SFL2) immune responses, evidenced by phosphorylation of MKP1 and c-Fos activation, key signal transducers in the hyphal invasion response. This profile of microcolony transcriptional regulators more closely reflects Sfl1 and Sfl2 hyphal regulatory networks than static biofilm regulatory networks, suggesting that microcolonies are a specialized pathogenic form of biofilm.
Asunto(s)
Candida albicans/genética , Candida albicans/patogenicidad , Biopelículas/crecimiento & desarrollo , Candida albicans/crecimiento & desarrollo , Candidiasis Bucal/etiología , Candidiasis Bucal/microbiología , Línea Celular , Recuento de Colonia Microbiana , Proteínas Fúngicas/genética , Redes Reguladoras de Genes , Genoma Fúngico , Humanos , Hifa/genética , Hifa/crecimiento & desarrollo , Hifa/patogenicidad , Mutación , Infecciones Oportunistas/etiología , Infecciones Oportunistas/microbiología , Factores de Transcripción/genética , Virulencia/genéticaRESUMEN
Candida albicans, the causative agent of mucosal infections, including oropharyngeal candidiasis (OPC), as well as bloodstream infections, is becoming increasingly resistant to existing treatment options. In the absence of novel drug candidates, drug repurposing aimed at using existing drugs to treat off-label diseases is a promising strategy. C. albicans requires environmental iron for survival and virulence, while host nutritional immunity deploys iron-binding proteins to sequester iron and reduce fungal growth. Here we evaluated the role of iron limitation using deferasirox (an FDA-approved iron chelator for the treatment of patients with iron overload) during murine OPC and assessed deferasirox-treated C. albicans for its interaction with human oral epithelial (OE) cells, neutrophils, and antimicrobial peptides. Therapeutic deferasirox treatment significantly reduced salivary iron levels, while a nonsignificant reduction in the fungal burden was observed. Preventive treatment that allowed for two additional days of drug administration in our murine model resulted in a significant reduction in the number of C. albicans CFU per gram of tongue tissue, a significant reduction in salivary iron levels, and significantly reduced neutrophil-mediated inflammation. C. albicans cells harvested from the tongues of animals undergoing preventive treatment had the differential expression of 106 genes, including those involved in iron metabolism, adhesion, and the response to host innate immunity. Moreover, deferasirox-treated C. albicans cells had a 2-fold reduction in survival in neutrophil phagosomes (with greater susceptibility to oxidative stress) and reduced adhesion to and invasion of OE cells in vitro Thus, deferasirox treatment has the potential to alleviate OPC by affecting C. albicans gene expression and reducing virulence.
Asunto(s)
Candida albicans/efectos de los fármacos , Candidiasis Bucal/tratamiento farmacológico , Deferasirox/farmacología , Células Epiteliales/microbiología , Quelantes del Hierro/farmacología , Mucosa Bucal/microbiología , Animales , Antifúngicos/farmacología , Candida albicans/patogenicidad , Candidiasis Bucal/microbiología , Candidiasis Bucal/patología , Adhesión Celular/efectos de los fármacos , Células Cultivadas , Reposicionamiento de Medicamentos , Femenino , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Humanos , Hierro/metabolismo , Ratones , Ratones Endogámicos C57BL , Mucosa Bucal/citología , Mucosa Bucal/patología , Neutrófilos/microbiología , Estrés Oxidativo/efectos de los fármacos , Saliva/química , Lengua/microbiologíaRESUMEN
Temperature is a potent inducer of fungal dimorphism. Multiple signalling pathways control the response to growth at high temperature, but the sensors that regulate these pathways are poorly defined. We show here that the signalling mucin Msb2 is a global regulator of temperature stress in the fungal pathogen Candida albicans. Msb2 was required for survival and hyphae formation at 42°C. The cytoplasmic signalling domain of Msb2 regulated temperature-dependent activation of the CEK mitogen activated proteins kinase (MAPK) pathway. The extracellular glycosylated domain of Msb2 (100-900 amino acid residues) had a new and unexpected role in regulating the protein kinase C (PKC) pathway. Msb2 also regulated temperature-dependent induction of genes encoding regulators and targets of the unfolded protein response (UPR), which is a protein quality control (QC) pathway in the endoplasmic reticulum that controls protein folding/degradation in response to high temperature and other stresses. The heat shock protein and cell wall component Ssa1 was also required for hyphae formation and survival at 42°C and regulated the CEK and PKC pathways.
Asunto(s)
Adaptación Fisiológica/genética , Candida albicans/metabolismo , Respuesta al Choque Térmico/fisiología , Péptidos y Proteínas de Señalización Intracelular/genética , Sistema de Señalización de MAP Quinasas/fisiología , Respuesta de Proteína Desplegada/genética , Candida albicans/genética , Candida albicans/crecimiento & desarrollo , Pared Celular/metabolismo , Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Regulación Fúngica de la Expresión Génica , Proteínas HSP70 de Choque Térmico/metabolismo , Calor , Hifa/genética , Hifa/crecimiento & desarrollo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteína Quinasa C/metabolismoRESUMEN
Candida albicans, a commensal fungus of the oral microbiome, causes oral candidiasis in humans with localized or systemic immune deficiencies. Secreted aspartic proteinases (Saps) are a family of 10 related proteases and are virulence factors due to their proteolytic activity, as well as their roles in adherence and colonization of host tissues. We found that mice infected sublingually with C. albicans cells overexpressing Sap6 (SAP6 OE and a Δsap8 strain) had thicker fungal plaques and more severe oral infection, while infection with the Δsap6 strain was attenuated. These hypervirulent strains had highly aggregative colony structure in vitro and higher secreted proteinase activity; however, the levels of proteinase activity of C. albicans Saps did not uniformly match their abilities to damage cultured oral epithelial cells (SCC-15 cells). Hyphal induction in cells overexpressing Sap6 (SAP6 OE and Δsap8 cells) resulted in formation of large cell-cell aggregates. These aggregates could be produced in germinated wild-type cells by addition of native or heat-inactivated Sap6. Sap6 bound only to germinated cells and increased C. albicans adhesion to oral epithelial cells. The adhesion properties of Sap6 were lost upon deletion of its integrin-binding motif (RGD) and could be inhibited by addition of RGD peptide or anti-integrin antibodies. Thus, Sap6 (but not Sap5) has an alternative novel function in cell-cell aggregation, independent of its proteinase activity, to promote infection and virulence in oral candidiasis.
Asunto(s)
Ácido Aspártico Endopeptidasas/metabolismo , Candida albicans/fisiología , Candidiasis Bucal/microbiología , Adhesión Celular , Proteínas Fúngicas/metabolismo , Factores de Virulencia/metabolismo , Animales , Ácido Aspártico Endopeptidasas/genética , Candida albicans/genética , Candidiasis Bucal/patología , Supervivencia Celular , Modelos Animales de Enfermedad , Células Epiteliales/microbiología , Femenino , Proteínas Fúngicas/genética , Eliminación de Gen , Ratones Endogámicos C57BL , Virulencia , Factores de Virulencia/genéticaRESUMEN
The geographical information system (GIS) has emerged as an efficient tool in delineation of drainage patterns of watershed planning and management. The morphometric parameters of basins can address linear, areal and relief aspects. The study deals with the integrated watershed management of Baliya micro-watersheds, located in the Udaipur district of Rajasthan, India. Morphometric analysis in hydrological investigation is an important aspect and it is inevitable in the development and management of drainage basins. The determination of linear, areal and relief parameters indicate fairly good significance. The low value of the bifurcation ratio of 4.19 revealed that the drainage pattern has not been distorted by structural disturbance. The high value of the elongation ratio (0.68) compared to the circulatory ratio (0.27) indicates an elongated shape of the watershed. The high value of drainage density (5.39 km/km(2)) and stream frequency (12.32) shows that the region has impermeable subsoil material under poor vegetative cover with a low relief factor. The morphometric parameters of relief ratio (0.041) and relative relief (0.99%) show that the watershed can be treated using GIS techniques to determine the morphometric presence of dendritic drainage pattern, with a view to selecting the soil and water conservation measures and water harvesting.
Asunto(s)
Conservación de los Recursos Naturales/métodos , Monitoreo del Ambiente/métodos , Sistemas de Información Geográfica , Movimientos del Agua , Hidrología , India , Lluvia , Ríos , Abastecimiento de AguaRESUMEN
Oropharyngeal candidiasis (OPC) is caused by the opportunistic fungi Candida albicans and is prevalent in immunocompromised patients, individuals with dry mouth, or patients with prolonged antibiotic therapies that reduce oral commensal bacteria. Human salivary histatins, including histatin 5 (Hst 5), are small cationic proteins that are the major source of fungicidal activity of saliva. However, Hsts are rapidly degraded in vivo, limiting their usefulness as therapeutic agents despite their lack of toxicity. We constructed a conjugate peptide using spermidine (Spd) linked to the active fragment of Hst 5 (Hst 54-15), based upon our findings that C. albicans spermidine transporters are required for Hst 5 uptake and fungicidal activity. We found that Hst 54-15-Spd was significantly more effective in killing C. albicans and Candida glabrata than Hst 5 alone in both planktonic and biofilm growth and that Hst 54-15-Spd retained high activity in both serum and saliva. Hst 54-15-Spd was not bactericidal against streptococcal oral commensal bacteria and had no hemolytic activity. We tested the effectiveness of Hst 54-15-Spd in vivo by topical application to tongue surfaces of immunocompromised mice with OPC. Mice treated with Hst 54-15-Spd had significant clearance of candidal tongue lesions macroscopically, which was confirmed by a 3- to 5-log fold reduction of C. albicans colonies recovered from tongue tissues. Hst 54-15-Spd conjugates are a new class of peptide-based drugs with high selectivity for fungi and potential as topical therapeutic agents for oral candidiasis.
Asunto(s)
Antifúngicos/farmacología , Candidiasis Bucal/tratamiento farmacológico , Candidiasis Bucal/microbiología , Histatinas/farmacología , Huésped Inmunocomprometido , Oligopéptidos/química , Espermidina/química , Administración a través de la Mucosa , Animales , Antifúngicos/química , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Transporte Biológico , Candida albicans/efectos de los fármacos , Candida albicans/crecimiento & desarrollo , Candida glabrata/efectos de los fármacos , Candida glabrata/crecimiento & desarrollo , Candidiasis Bucal/inmunología , Femenino , Histatinas/química , Humanos , Ratones , Mucosa Bucal/efectos de los fármacos , Mucosa Bucal/inmunología , Mucosa Bucal/microbiología , Plancton/efectos de los fármacos , Plancton/crecimiento & desarrolloRESUMEN
Histatin 5 (Hst 5) is a salivary human antimicrobial peptide that is toxic to the opportunistic yeast Candida albicans. Fungicidal activity of Hst 5 requires intracellular translocation and accumulation to a threshold concentration for it to disrupt cellular processes. Previously, we observed that total cytosolic levels of Hst 5 were gradually reduced from intact cells, suggesting that C. albicans possesses a transport mechanism for efflux of Hst 5. Since we identified C. albicans polyamine transporters responsible for Hst 5 uptake, we hypothesized that one or more polyamine efflux transporters may be involved in the efflux of Hst 5. C. albicans FLU1 and TPO2 were found to be the closest homologs of Saccharomyces cerevisiae TPO1, which encodes a major spermidine efflux transporter, indicating that the products of these two genes may be involved in efflux of Hst 5. We found that flu1Δ/Δ cells, but not tpo2Δ/Δ cells, had significant reductions in their rates of Hst 5 efflux and had significantly higher cytoplasmic Hst 5 and Hst 5 susceptibilities than did the wild type. We also found that flu1Δ/Δ cells had reduced biofilm formation compared to wild-type cells in the presence of Hst 5. Transcriptional levels of FLU1 were not altered over the course of treatment with Hst 5; therefore, Hst 5 is not likely to induce FLU1 gene overexpression as a potential mechanism of resistance. Thus, Flu1, but not Tpo2, mediates efflux of Hst 5 and is responsible for reduction of its toxicity in C. albicans.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Candida albicans/metabolismo , Proteínas Fúngicas/metabolismo , Histatinas/metabolismo , Transportadoras de Casetes de Unión a ATP/genética , Candida albicans/efectos de los fármacos , Candida albicans/genética , Resistencia a Múltiples Medicamentos/genética , Proteínas Fúngicas/clasificación , Proteínas Fúngicas/genética , Histatinas/clasificación , Histatinas/genética , Humanos , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Espermidina/metabolismoRESUMEN
Reliable information on the horizontal and vertical dimensions of the wetted soil beneath a point source is critical for designing accurate, cost-effective, and efficient surface and subsurface drip irrigation systems. Several factors, including soil properties, initial soil conditions, dripper flow rate, number of drippers, spacing between drippers, irrigation management, plant root characteristics, and evapotranspiration, influence the dimensions and shape of wetting patterns. The objective of this study was to briefly review previous studies, collect the analytical, numerical, and empirical models developed, and evaluate the effectiveness of the most common empirical method for predicting the dimensions of soil wetted around drippers using measured data from field surveys. With this review study, we aim to promote a better understanding of soil water dynamics under point-source drip irrigation systems, help improve soil water dynamics under point-source drip irrigation systems, and identify issues that should be better addressed in future modeling efforts. A drip irrigation system was configured with three different emitters with different capacities (2, 4, and 8 l h-1) in the point source to determine the soil wetting front under the point source. The five most selected empirical equations (Al-Ogaidi, Malek and Peters, Amin and Ekhmaj, Li and Schwartzman and Zur) were statistically analyzed to test the efficiency in sandy loam soil. According to the results of the field investigation, statistical comparisons of the empirical models with the field investigation data were performed using the mean absolute error (MAE), root mean square error (RMSE), Nash-Sutcliffe model efficiency (CE), and coefficients of determination (R2). The advanced simulation of the wetting front was used based on the best accuracy of the selected empirical model. In general, the Li model (MAE, RMSE, EF, and R2 were 0.698 cm, 0.894 cm, 0.970 cm2 cm-2, and 0.970, respectively, for the wetted soil width and 1.800 cm, 1.974 cm, 0.927 cm2 cm-2, and 0.986, for the vertical advance) proved to be the best after statistical analysis with field data.
RESUMEN
Oral mucosal colonization by C. albicans (Ca) is benign in healthy people but progresses to deeper infection known as oropharyngeal candidiasis (OPC) that may become disseminated when combined with immunosuppression. Cortisone-induced immunosuppression is a well-known risk factor for OPC, however the mechanism by which it permits infection is poorly understood. Neutrophils are the primary early sentinels preventing invasive fungal growth, and here we identify that in vivo neutrophil functional complexes known as swarms are crucial for preventing Ca invasion which are disrupted by cortisone. Neutrophil swarm function required leukotriene B4 receptor 1 (BLT1) expression, and swarms were further characterized by peripheral association of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) showing that OPC recruits PMN-MDSCs to this site of infection. Furthermore, PMN-MDSCs associated with Ca hyphae had no direct antifungal effect but showed prolonged survival times and increased autophagy. Thus in vivo neutrophil swarms are complex structures with spatially associated PMN-MDSCs that likely contribute immunoregulatory functions to resolve OPC. These swarm structures have an important function in preventing deep invasion by Ca within the oral mucosa and represent a mechanism for increased disease severity under immune deficient clinical settings.
RESUMEN
Trash mulches are remarkably effective in preventing soil erosion, reducing runoff-sediment transport-erosion, and increasing infiltration. The study was carried out to observe the sediment outflow from sugar cane leaf (trash) mulch treatments at selected land slopes under simulated rainfall conditions using a rainfall simulator of size 10 m × 1.2 m × 0.5 m with the locally available soil material collected from Pantnagar. In the present study, trash mulches with different quantities were selected to observe the effect of mulching on soil loss reduction. The number of mulches was taken as 6, 8 and 10 t/ha, three rainfall intensities viz. 11, 13 and 14.65 cm/h at 0, 2 and 4% land slopes were selected. The rainfall duration was fixed (10 minutes) for every mulch treatment. The total runoff volume varied with mulch rates for constant rainfall input and land slope. The average sediment concentration (SC) and sediment outflow rate (SOR) increased with the increasing land slope. However, SC and outflow decreased with the increasing mulch rate for a fixed land slope and rainfall intensity. The SOR for no mulch-treated land was higher than trash mulch-treated lands. Mathematical relationships were developed for relating SOR, SC, land slope, and rainfall intensity for a particular mulch treatment. It was observed that SOR and average SC values correlated with rainfall intensity and land slope for each mulch treatment. The developed models' correlation coefficients were more than 90%.
Asunto(s)
Sedimentos Geológicos , Erosión del Suelo , Lluvia , Suelo , ChinaRESUMEN
The design and selection of ideal emitter discharge rates can be aided by accurate information regarding the wetted soil pattern under surface drip irrigation. The current field investigation was conducted in an apple orchard in SKUAST- Kashmir, Jammu and Kashmir, a Union Territory of India, during 2017-2019. The objective of the experiment was to examine the movement of moisture over time and assess the extent of wetting in both horizontal and vertical directions under point source drip irrigation with discharge rates of 2, 4, and 8 L h-1. At 30, 60, and 120 min since the beginning of irrigation, a soil pit was dug across the length of the wetted area on the surface in order to measure the wetting pattern. For measuring the soil moisture movement and wetted soil width and depth, three replicas of soil samples were collected according to the treatment and the average value were considered. As a result, 54 different experiments were conducted, resulting in the digging of pits [3 emitter discharge rates × 3 application times × 3 replications × 2 (after application and 24 after application)]. This study utilized the Drip-Irriwater model to evaluate and validate the accuracy of predictions of wetting fronts and soil moisture dynamics in both orientations. Results showed that the modeled values were very close to the actual field values, with a mean absolute error of 0.018, a mean bias error of 0.0005, a mean absolute percentage error of 7.3, a root mean square error of 0.023, a Pearson coefficient of 0.951, a coefficient of correlation of 0.918, and a Nash-Sutcliffe model efficiency coefficient of 0.887. The wetted width just after irrigation was measured at 14.65, 16.65, and 20.62 cm; 16.20, 20.25, and 23.90 cm; and 20.00, 24.50, and 28.81 cm in 2, 4, and 8 L h-1, at 30, 60, and 120 min, respectively, while the wetted depth was observed 13.10, 16.20, and 20.44 cm; 15.10, 21.50, and 26.00 cm; 19.40, 25.00, and 31.00 cm, respectively. As the flow rate from the emitter increased, the amount of moisture dissemination grew (both immediately and 24 h after irrigation). The soil moisture contents were observed 0.4300, 0.3808, 0.2298, 0.1604, and 0.1600 cm3 cm-3 just after irrigation in 2 L h-1 while 0.4300, 0.3841, 0.2385, 0.1607, and 0.1600 cm3 cm-3 were in 4 L h-1 and 0.4300, 0.3852, 0.2417, 0.1608, and 0.1600 cm3 cm-3 were in 8 L h-1 at 5, 10, 15, 20, and 25 cm soil depth in 30 min of application time. Similar distinct increments were found in 60, and 120 min of irrigation. The findings suggest that this simple model, which only requires soil, irrigation, and simulation parameters, is a valuable and practical tool for irrigation design. It provides information on soil wetting patterns and soil moisture distribution under a single emitter, which is important for effectively planning and designing a drip irrigation system. Investigating soil wetting patterns and moisture redistribution in the soil profile under point source drip irrigation helps promote efficient planning and design of a drip irrigation system.
RESUMEN
Histatin 5 (Hst 5) is a salivary gland-secreted cationic peptide with potent fungicidal activity against Candida albicans. Hst 5 kills fungal cells following intracellular translocation, although its selective transport mechanism is unknown. C. albicans cells grown in the presence of polyamines were resistant to Hst 5 due to reduced intracellular uptake, suggesting that this cationic peptide may enter candidal cells through native yeast polyamine transporters. Based upon homology to known Saccharomyces cerevisiae polyamine permeases, we identified six C. albicans Dur polyamine transporter family members and propose a new nomenclature. Gene deletion mutants were constructed for C. albicans polyamine transporters Dur3, Dur31, Dur33, Dur34, and were tested for Hst 5 sensitivity and uptake of spermidine. We found spermidine uptake and Hst 5 mediated killing were decreased significantly in Δdur3, Δdur31, and Δdur3/Δdur31 strains; whereas a DUR3 overexpression strain increased Hst 5 sensitivity and higher spermidine uptake. Treatment of cells with a spermidine synthase inhibitor increased spermidine uptake and Hst 5 killing, whereas protonophores and cold treatment reduced spermidine uptake. Inhibition assays showed that Hst 5 is a competitive analog of spermidine for uptake into C. albicans cells, and that Hst 5 Ki values were increased by 80-fold in Δdur3/Δdur31 cells. Thus, Dur3p and Dur31p are preferential spermidine transporters used by Hst 5 for its entry into candidal cells. Understanding of polyamine transporter-mediated internalization of Hst 5 provides new insights into the uptake mechanism for C. albicans toxicity, and further suggests design for targeted fungal therapeutic agents.
Asunto(s)
Candida albicans/metabolismo , Proteínas de Transporte de Catión/metabolismo , Regulación Fúngica de la Expresión Génica , Histatinas/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Poliaminas/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Antiinfecciosos/farmacología , Unión Competitiva , Compuestos de Boro/química , Proteínas de Transporte de Catión/química , Cinética , Proteínas de Transporte de Membrana/química , Microscopía Confocal/métodos , Filogenia , Plásmidos/metabolismo , Transporte de Proteínas , Proteínas de Saccharomyces cerevisiae/química , Espermidina/química , Factores de TiempoRESUMEN
Candida albicans Sap6, a secreted aspartyl protease (Sap), contributes to fungal virulence in oral candidiasis. Beside its protease activity, Sap6 contains RGD (RGDRGD) motif required for its binding to host integrins. Sap6 activates immune cells to induce proinflammatory cytokines, although its ability to interact and activate human oral epithelial cells (OECs) remain unknown. Addition of purified recombinant Sap6 (rSap6) to OECs resulted in production of IL-1ß and IL-8 cytokines similar to live hyphal C. albicans. OECs exposed to rSap6 showed phosphorylation of p38 and MKP1 and expression of c-Fos not found with C. albicans Δsap6, heat-inactivated Sap6, or rSap6ΔRGD . Heat inactivated rSap6 was able to induce IL-1ß but not IL-8 in OECs, while rSap6ΔRGD induced IL-8 but not IL-1ß suggesting parallel signaling pathways. C. albicans hyphae increased surface expression of Protease Activated Receptors PAR1, PAR2 and PAR3, while rSap6 increased PAR2 expression exclusively. Pretreatment of OECs with a PAR2 antagonist blocked rSap6-induced p38 MAPK signaling and IL-8 release, while rSap6ΔRGD had reduced MKP1 signaling and IL-1ß release independent from PAR2. OECs exposed to rSap6 exhibited loss of barrier function as measured by TEER and reduction in levels of E-cadherin and occludin junctional proteins that was prevented by pretreating OECs with a PAR2 antagonist. OECs treated with PAR2 antagonist also showed reduced rSap6-mediated invasion by C. albicans cells. Thus, Sap6 may initiate OEC responses mediated both through protease activation of PAR2 and by its RGD domain. This novel role of PAR2 suggests new drug targets to block C. albicans oral infection.
Asunto(s)
Ácido Aspártico Endopeptidasas/metabolismo , Candida albicans , Proteínas Fúngicas/metabolismo , Receptor PAR-2/metabolismo , Estomatitis/microbiología , Citocinas/metabolismo , Interacciones Huésped-Patógeno , Humanos , Inflamación , Receptores Proteinasa-Activados/metabolismoRESUMEN
Nanotechnology is being an emerging science for wastewater treatment requires more research emphasis and depth knowledge. For wastewater treatment, different forms of nanomaterials are used based on the type of contaminants and treatment efficiency desired. With the development in the field of nanomaterials, novel and emerging nanomaterials are coming into existence. The nanomaterials used for wastewater treatment can be carbon, single-walled carbon nanotubes, multiple walled carbon nanotubes, covalent organic frameworks, metal and metal oxide- based nanoparticles. Graphene based nanoparticles, their oxides (GO) and reduced graphene oxide (rGO) find tremendous applicability to be used in wastewater treatment purposes. Due to the introduction of graphene oxide nanoparticles in the adsorbent materials, their adsorption capacities have get enhanced and such materials have also improved the mechanical stability of the adsorbent. Ferric oxide shows greater adsorption capacities for organic pollutants. Furthermore, magnetic nano-powder confers a low adsorption capacity for phenols. Pyrrolidone reduced graphene oxide (PVP-RGO) nanoparticles have been used as adsorbents for the elimination of inorganic target contaminant copper, with great adsorption (1698 mg/g). The present study comprehensively reviews nanotechnology as a wastewater treatment strategy besides enlightening its safety issues and efficiency. The novelty of this article is that it highlights the overview of recent applications of various types of nanomaterials and research works releated to it. Such an approach will be helpful to get insights into technological advances, applications and future challenges of nanotechnology implementation for wastewater treatment.
Asunto(s)
Grafito , Nanotubos de Carbono , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Nanotecnología , Aguas ResidualesRESUMEN
Coronavirus refers to a group of widespread viruses. The name refers to the specific morphology of these viruses because their spikes look like a crown under an electron microscope. The outbreak of coronavirus disease 2019 (COVID-19) that has been reported in Wuhan, China, in December 2019, was proclaimed an international public health emergency (PHEIC) on 30 January 2020, and on 11 March 2020, it was declared as a pandemic (World Health Organization 2020). The official name of the virus was declared by the WHO as "COVID-19 virus", formerly known as "2019-nCoV", or "Wuhan Coronavirus". The International Committee on Virus Taxonomy's Coronavirus Research Group has identified that this virus is a form of coronavirus that caused a severe outbreak of acute respiratory syndrome in 2002-2003 (SARS). As a result, the latest severe acute respiratory syndrome has been classified as a corona virus 2 (SARS-CoV-2) pathogen by this committee. This disease spread quickly across the country and the world within the first 3 months of the outbreak and became a global pandemic. To stop COVID-19 from spreading, the governing agencies used various chemicals to disinfect different commercial spaces, streets and highways. However, people used it aggressively because of panic conditions, anxiety and unconsciousness, which can have a detrimental impact on human health and the environment. Our water bodies, soil and air have been polluted by disinfectants, forming secondary products that can be poisonous and mutagenic. In the prevention and spread of COVID-19, disinfection is crucial, but disinfection should be carried out with sufficient precautions to minimize exposure to harmful by-products. In addition, to prevent inhalation, adequate personal protective equipment should be worn and chemical usage, concentrations, ventilation in the room and application techniques should be carefully considered. In the USA, 60% of respondents said they cleaned or disinfected their homes more often than they had in the previous months. In addition to the robust use of disinfection approaches to combat COVID-19, we will explore safe preventative solutions here.
Asunto(s)
COVID-19 , Desinfectantes , Humanos , SARS-CoV-2 , Pandemias/prevención & control , Brotes de EnfermedadesRESUMEN
Dams significantly impact river hydrology by changing the timing, size, and frequency of low and high flows, resulting in a hydrologic regime that differs significantly from the natural flow regime before the impoundment. For precise planning and judicious use of available water resources for agricultural operations and aquatic habitats, it is critical to assess the dam water's temperature accurately. The building of dams, particularly several dams in rivers, can significantly impact downstream water. In this study, we predict the daily water temperature of the Yangtze River at Cuntan. Thus, this work reveals the potential of machine learning models, namely, M5 Pruned (M5P), Random Forest (RF), Random Subspace (RSS), and Reduced Error Pruning Tree (REPTree). The best and effective input variables combinations were determined based on the correlation coefficient. The outputs of the various machine learning algorithm models were compared with recorded daily water temperature data using goodness-of-fit criteria and graphical analysis to arrive at a final comparison. Based on a number of criteria, numerical comparison between the models revealed that M5P model performed superior (R2 = 0.9920, 0.9708; PCC = 0.9960, 0.9853; MAE = 0.2387, 0.4285; RMSE = 0.3449, 0.4285; RAE = 6.2573, 11.5439; RRSE = 8.0288, 13.8282) in pre-impact and post-impact spam, respectively. These findings suggest that a huge wave of dam construction in the previous century altered the hydrologic regimes of large and minor rivers. This study will be helpful for the ecologists and river experts in planning new reservoirs to maintain the flows and minimize the water temperature concerning spillway operation. Finally, our findings revealed that these algorithms could reliably estimate water temperature using a day lag time input in water level. They are cost-effective techniques for forecasting purposes.
Asunto(s)
Hidrología , Ríos , Temperatura , Aprendizaje Automático , AguaRESUMEN
Candida albicans is maintained as a commensal by immune mechanisms at the oral epithelia. Oral antifungal peptide Histatin 5 (Hst 5) may function in innate immunity, but the specific role Hst 5 plays in C. albicans commensalism is unclear. Since Zn-binding potentiates the candidacidal activity of Hst 5, we hypothesized that Hst 5+Zn would elicit a unique fungal stress response to shape interactions between C. albicans and oral epithelial cells (OECs). We found that Hst 5+Zn but not Hst 5 alone resulted in the activation of cell wall integrity (CWI) signaling, and deletion mutants were then used to determine that CWI-mediated chitin synthesis was protective against killing. Using flow cytometry, we confirmed that Hst 5+Zn-treated cells had significantly elevated levels of cell-wall chitin, mannan and ß-1,3 glucan compared to Hst 5-treated cells. We then tested the activation of host signaling components involved in C. albicans cell-wall recognition. The immunoblot assay of C. albicans-exposed oral epithelial cells showed increased activation of EphA2 and NF-κB but not EGFR. Interestingly, C. albicans treated with Hst 5+Zn induced the global suppression of pro-inflammatory cytokine release from OECs, but an increase in negative regulator IL-10. Hst 5+Zn-treated cells were more adherent but ultimately less invasive to OECs than control cells, thus indicating lowered virulence. Therefore, Hst 5+Zn-treated C. albicans cells are discerned by epithelial monolayers, but are less virulent and promote anti-inflammatory signaling, suggesting that Hst 5+Zn in combination could play a role in regulating commensalism of oral C. albicans through cell wall reorganization.
RESUMEN
Candida albicans is an opportunistic, dimorphic fungus that causes candidiasis in immunocompromised people. C. albicans forms specialized structures called microcolonies that are important for surface adhesion and virulence. Microcolonies form in response to specific environmental conditions and require glycolytic substrates for optimal growth. However, fungal signaling pathways involved in sensing and transmitting these environmental cues to induce microcolony formation have not been identified. Here, we show that the C. albicans Ras1-cAMP cascade is required for microcolony formation, while the Cek1-MAP kinase pathway is not required, and Hog1 represses microcolony formation. The membrane protein Sho1, known to regulate the Cek1 pathway in yeasts, was indispensable for C. albicans microcolony formation but regulated the Ras1-cAMP pathway instead, based upon diminished intracellular levels of cAMP and reduced expression of core microcolony genes, including HWP1, PGA10, and ECE1, in C. albicanssho1Δ cells. Based upon predicted physical interactions between Sho1 and the glycolytic enzymes Pfk1, Fba1, Pgk1, and Cdc19, we hypothesized that Sho1 regulates Ras1-cAMP by establishing cellular energy levels produced by glycolysis. Indeed, microcolony formation was restored in C. albicanssho1Δ cells by addition of exogenous intermediates of glycolysis, including downstream products of each predicted interacting enzyme (fructose 1,6 bisphosphate, glyceraldehyde phosphate, 3-phosphoglyceric acid, and pyruvate). Thus, C. albicans Sho1 is an upstream regulator of the Ras1-cAMP signaling pathway that connects glycolytic metabolism to the formation of pathogenic microcolonies.IMPORTANCEC. albicans microcolonies form extensive hyphal structures that enhance surface adherence and penetrate underlying tissues to promote fungal infections. This study examined the environmental conditions that promote microcolony formation and how these signals are relayed, in order to disrupt signaling and reduce pathogenesis. We found that a membrane-localized protein, Sho1, is an upstream regulator of glycolysis and required for Ras1-cAMP signaling. Sho1 controlled the Ras1-dependent expression of core microcolony genes involved in adhesion and virulence. This new regulatory function for Sho1 linking glycolysis to microcolony formation reveals a novel role for this fungal membrane protein.